In recent years, for example, as a mobile communication base station or an antenna device for a Wi-Fi communication device, a multi-band antenna capable of communicating in a plurality of frequency bands is provided for practical use in order to ensure communication capacity (Wi-Fi is a registered trademark).
For example, a multi-band antenna is disclosed in FIG. 11, FIG. 12, and FIG. 13 of Patent Document 1, or Patent Document 2 and the like. In particular, in the multi-band antenna disclosed in Patent Document 1, there is disclosed a technique for realizing a multi-band antenna by using a plurality of dipole antenna elements supporting each frequency band.
In this multi-band antenna, crossed-dipole antenna elements for high band and low band are arranged alternately on the antenna reflector so as to form arrays. In addition, central conductor fences are provided between the arrays to reduce mutual coupling.